Method and apparatus for the production of music



June 27, 1933;

c. T. JACOBS ammo];

AND APPARATUS FOR THE PRODUCTION OF MUSIC Original Filed Sept. 22, 19312- Sheets-Sheet, 1

IN V EN TOR.'- I

June 27, 1933.

c. JACOBS 1,915,861

METHOD AND APPARATUS FOR THE PRODUCTION OF MUSIC 4 Original Filed Sept.22, 1931 2 Sheets-Sheet. 2

II I

TUBE 2! INKENTOR:- W

Patented June 27, 1933 UNITED STATES.

PATENT OFFICE.

CHARLES T. JACOBS, NEW PROV'l'DENGE TOWNSHIP, UNION COUNTY, NEW JERSEY,ASSIGNOR TO MIESSNER INVENTIONS, INC.,- A CORPORATION OF NEW JERSEYMETHOD AND APPARATUS FOR THE PRODUCTION OF MUSIC Application filedSeptember 22, 1931, Serial No. 564,305. Renewed November 17, 1932.

' mental frequency component but also one or more coincident higherfrequency compo.- nents harmonically related to the fundamental. Thefundamental and these higher frequency components may each be termed apartial of the composite vibration. Typical of such vibrators are,ofcourse, strings under. longitudinal tension; and strings are shown asthe vibrators in the accompanying drawings. I do not wish to limit myinvention to use with strings, however, it being adaptable for use withany other such tuned vibrator as above mentioned.

- In the. U. S. Patent 1,906,607, issued to me' -May 2, 1933, I pointedout that the oscillations produced by translation of the vibrations ofthe various points on a vibrating string were of different waveform; butthat while an infinite number of such waveforms were available by suchtranslation at different points, they did not represent as large aspossible a variety of tone qualities. I

showed, however, that if oscillations produced by translation of theVibrations of two or more string points were combined, new

tone qualities became available; and further, that if theseveral'oscillations were controllable before combination in respect ofrelative amplitudes and relative phases, an extremely wide variation infinal waveform and harmonic structure, and hence tone quality, could beeffected. Methods and apparatus were disclosed in that application forsuch multi-point translation, relative amplitude andphase control, andsubsequent combination of oscillations. The present applicationissconcerned principally with extensions and modifications of the. meansand methods therein disclosed, together with specific means and methodsfor producingmore particular types of .output tones.

Thus it is an object of my invention to provide improved means andmethods for translating the vibrations of tuned vibrators into electricoscillations of a harmonic structure selectable within wide limits;andlikewise for selectively varying over a wide range the harmonicstructure or waveform of electric oscillations produced by translationof the vibrations of tuned vibrators.

A further object is the provision in a musical instrument of the classdescribed of improved vibration-oscillation means and methods suitablefor producing almost any desired quality of tone; and likewise suchmeans and methods for producing a quallty of tone selectively variableover a wide range. Y i

It is another object of myinvention to provide lmproved and convenientcontrols for effecting the variation and selection abovementioned; andmore specific objects are the provision of means and methods forobtaining'from the vibrations of tuned Vibrators electric oscillationsof various particular harmonic structures: e. g., containing only orpredominately even or odd numbered electrical and electro-acousticapparatus embodying my invention;

Figure 2 1s a partial plan view of the mechanical apparatus shown inFigure 1;

Figure 3 is a view similar-to Figure 2' butillustrating an alternativeplan arrangement of the mechanical apparatus shown in Figure l; and

translating .partial components, containing substantial- Figure 4 is afurther cross-sectional view of a string and its supports illustrating aparticular arrangement of translating devices adapted to the productionof practically pure fundamental frequency oscillations from stringvibrations having appreciable upper partial components.

the latter, but it will be understood that any means or device forproducing either sustained or decadent vibration of the string at itsfundamental and at least one harmonic frequency may be substituted forhammer 8. A plan view of this apparatus showing a group of strings 1 ofprogressive lengths for vibration at progressive frequencies of themusical scale appears as Figure 2.

Below the several strings 1 will be seen, in both Figures 1 and 2,conductive strips 9, 10 and 11, preferably of small cross-section, andabove the several strings similar conductive strips 12 and 13. Thesestrips may conveniently be supported by somewhat flexible insulatingstrips 14, to which the conductive strips may be cemented, as is morefully disclosed in the co-pending application of Benjamin F. Miessnerand .myself, Serial No. 558,207, filed August 20, 1931. The conductivestrips will each be seen to be slightly spaced from each of the strings1; and such spacing is in general preferably as small as possiblewithout producing any contact betweenthe strips and any string 1 underconditions of maximum vibration of the latter. It will be appreciated,of course, that such spacing of a conductive strip will in general begreater, the nearer such strip to the center of the strings. Whileparticular means of securing the insulating strips 14 have beendisclosed in the joint co-pending' application abovementioned, it issuflicient for the purposes of this specification that they be. se-

cured in any convenient manner preserving the insulation aiforded bythem to theseveral conductive strips 9, 10, 11, 12 and 13 affixedthereto.

The conductive strips may be electrically connected, through variousswitching arrangements comprising group of switches 15, group .16, anddouble pole double throw switch 17, hereinafter more fully discussed, tothe grids of a plurality of vacuum-tubes shown in Figure 1 as 21, 22 and23. .The cathodes or filaments of the tubes may be connected togetherand energized as by battery 24. A tap 25 on battery or other potentialsource 26 may rovide a source of anode current for thetu s. Between thecathodes'of the tubes and the'negative of battery 26 may be provided acondensively -by-passed resistor 27 for the biasing of the grid of eachtube, throu h an associated high resistance 28, negative y with respectto its cathode. In

the output circuit of each tube may be connected the primary of atransformer, such electrical center of the associated tapped re-'sistor, such switch in each bank being designated as 54. The eletricalcenters of the tapped resistors, and the common connection of eachswitch-bank, may be connected together as shown and to the potentiometer29;

and the variable contact of this potentiome ter may be connected to thegrid of a fourth vacuum tube 34. The cathode or filament of this tubemay conveniently be paralleled with those of tubes 21, 22 and 23; andits anode current may be supplied from the tap 25 on battery 26. In theoutput circuit of this tube may be connected amplifier 35; and to theamplifier may be connected loudspeaker 36. Electrostatic shielding 37may be disposed about the tubes 21, 22, 23 and 34 and their associatedcircuits, about the leads thereto from the conductive strips 9, 10, 11,12 and 13, and around such strips. Such shielding may be connected tothe positive terminal of battery or potential source 26 and also to capo6 orto some othermember or members electrically connectedto strings 1,

' whereby the latter may be rendered at the potential of such positiveterminal of battery or. source 26. It willbe' understood, of course,that tubes with unipotential cathodes suitably ener ized fromalternating current may be substituted fortubes 21, 22, 23 and 34 andbattery 24; likewise that a suitable rectifying, filtering and (voltagedividing.

system may replace battery or source 26, etc.

Consideration being given to the manner of functioning of the apparatusshown in Figure 1, it will be seen that between each strip 9, 10, 11,12' and 13 and each string 1 a small electrostatic capacity exists; andthat, with the switches in groups 15 and 16 open and switch 17 in thelefthand position. as shown, thetotal capacity formed between each oneof the strips 9, 10, and 11 is in series with one of the resistors 28and the battery 26. These capacities are therefore charged to thepotential of battery 26. Upon vibra-' tion of any string 1 in a verticalplane, as'produced by impact therewith of hammer 8, the capacity betweenstrip 9 and the re ion of such strin immediatel thereabove will varyoscillatori y, as'will l' ewise but in less degrce the total capacitybetween strip 9 and ages, in amplified form, respectively appear thestrings. This oscillatory capacity variation, because of the fixedcharge in the ca-- pacity, produces an'oscillatory variation of thevoltage across the capacity. The frequency, waveform and harmonicstructure of this voltage variation correspond respectively to the likecharacteristics of the vibration of the mean point of the vibratedstring opposite strip 9; and such oscillatory voltage variation, or A.C. voltage, is applied to the grid of tube 21. Similarly an A. C.voltage corresponding in its characteristics to the vibration of themean point of the vibrated string above strip 10 appears at the grid oftube 22; and a voltage corresponding to the vibration of the mean stringpoint above strip 11 at the grid of tube 23. These voltacross the tappedresistors 41, 42- and 43, as will be understood.

If now there'be closed one switch of each bank, other for example thanswitch 54, there will be seen to beprovided a continuous circuitincluding aportion of each of the tapped resistors 41, 42 and 4:3, andincluding the potentioineter 29. Thus voltages appearing across thethree tapped resistors may be made to appear in combination acrosspotentiometer 29; and it will be seen that the absolute (and hence therelative) amplitudes, of these several voltages may be regulated, andthat the absolute (and hence relative) phases thereof may be reversed atwill, by

choice of the switch closed in each bank; Elimination from potentiometer29 of volt age derived'from anyone or more of the tappedresistors may beeffected by closing the switch 54 in the associated switch bank,

whether or not other switches in that bank be closed; or by closing twoor more switches connected to taps on opposite sides of the electricalcenter of the resistance. Furthermore certain'amplitudes of voltage notavailable upon closing of any one switch in a bank may be obtained byclosing two or more switches connected to taps on the same sideassociated switch open and the other maintaining it closed.

The composite voltage made 'to appear across potentiometer 29 may bethereby regulated in amplitude; and may thereafter be amplified by tube34 and amplifier 35 and.

translated into sound'by loudspeaker 36.

The choice of position of the various conductive strips associated withthe various strings determines to a large extent the types and range oftone qualities available from the system. In general, as might beexpected from the segmental nature of the vibration of a string at itsvarious harmonically related partialfrequencies, the nearer the centerof the string a translating device be.

of the combining means-e. g., the switchbanks 51, 52 and 53that suchcancellation can be effected; and in order that the fullest advantage bederived from the wide range of combining adjustments available in agiven case, it is desirable that the oscillations produced by thecombining adjustment which most accentuates the lower partials, besufficiently rich in higher partials to make them ordinarily musicallyuseful. Then the adjustments which 'mostelfectively cancel out the lowerpartials need not be invariably employed, instead being available forthe production when desired of harmonic structures especially rich inhigher partials. To this end I have in general found it desirable toemploy translating devices relatively. near the extremities of thestrings. Thus strips 9, 10 and 11 in Figures 1 and 2 are respectivelyshown at approximately 1/20, 1/12 and 1/8 of the length of each stringforward from the rear end of the active vibratory portion thereof It ispossible, however, to obtain a harmonic structure very rich in higherpartials without positioning of translating device or system extremelynear the extremities of the strings, and without special adjustments -ofthe combining controls. This may be accomplished by employing twotranslating devices or systems permanently or optionally connectedtogether independently of the combining controls, and so arrangedthat'the lower partial components produced by each oppose each other'.Thus in Figuresl and 2 I show conductive strip 12 positioned atapproximately 1/6. of the length of each string forward from the rearend of the active portion thereof, and group of switches 15,'by'one ofwhich it may optionally be connected in parallel with strip 11,'which asabove-mentioned is positioned at approximately 1/8 string length forwardfrom the rear ends. It is important, with a capacitive translatingdevice and for the purpose at may be effected without positioning onopposite sides of the string, as will be understood.

When strip 12 is parallel with strip 11, the combination yieldsoscillations equivalent, in relative weakness of the lower partials, tothose produced by a' single strip much nearer the end-of the string thaneither of them.

. A special arrangement of translating devices very useful for theproduction of colorful tonal effects, for frequency doubling or for themore or lesscomplete elimination of even partials from oscillations andoutput tones, is the use of translating devices at least approximatelysimilarly spaced from the two ends of the active vibratory portion ofeach string-i. e., symmetrical longitudinally about the center ofthest'ring. Thus in Figtures 1 and 2 I show conductive strip 13positioned at approximately 1/20'of string length back of the forwardends of the several strings 1,-a similar spacing to that of strip 9 fromthe rear ends. By setting the switch 17 in the right-hand positioninstead of the left-hand position as shown, it will be seen that strip13 is substituted for strip 11, making active the three strips 9, 10 and13. If now switch 54 of bank 52 be closed, so that strip 10 is inactivein contributing to the final oscillations, there remain active thesymmetrically placed strips 9 and 13. If .the separate outputs from eachof these two strips be adjusted to introducev into the circuit ofpotentiometer 29 similar amplitudes and aiding phase of the fundamentalcomponent, by

closing of appropriate switches in banks 51 and 53, the combinedoscillations will be without even partials. If the similarity ofamplitudes -ofthe separate oscillations be somewhat upset, the combinedoscillations will have some even, but will predominate in odd, partials.Ifsimilarity of amplitude but opposition of fundamental phase beestablished by'theswitch-banks 51 a'nd53, the

combined oscillations will be without the original fundamental frequencyor other odd partials, thus producing the octave of the stringfrequency. If the fundamental phase opposition be maintainedbutamplitude similarity somewhat upset, the combined oscillations willcontain some odd, but will predominate in even, partials. Again, smallor large amplitudes of oscillations in. either phase from strip 10 maybe combined with the various combinations from strips 9 and 13; or withoscillations from strip 13 alone, in which latter case the resultingoscillations Will be characterized by incomplete tendencies toward evenor odd partial predominance, the two strips 10 and 13 being in a mostgeneral sense but by no means exactly, symmetrically placed about thecenter of the string.

Asdong as strip 13 is to be used alone to supply oscillations to tube23' and switchbank 53, it is of no significance whether it be placedabove or below the strings 1. But in order that it may on occasion becombined in parallel with other strips by group of switches 16, and tothe end that it may then serve in general to emphasize even partialsrather than odd, it has been shown on the opposite side of the stringsfrom the strips 9, 10 and 11. It may be noted that a strong tendencytoward even partial predominance may at times give the musical effect ofcoincident playing of higher octaves-of the notes actually played.

Switches such as groups 15 and 16, which possible without considerablymore complex.

apparatus. Thus, while more than three separate input tubes andswitch-banks may be employed, the use of switches performing suchfunctions as 15, 16 and/or 17 makes possible almost as wide harmonicstructure control without such additional apparatus.

The number of separate input tubes may even be reduced to two withouttremendous sacrifices of the flexibility of the system if suitableswitches such as 15, 16 and 17 be employed. Switches in the groups 15and 16 and double pole double throw switch 17, i

being each a two position switch, may convem'ently be controlled bvtabletsas abovementioned for the switches in the banks 51, 52 and 53.

For purposes .of simulation of the tone quality of particularinstruments, or for any of several possible-reasons dictating aparticular choice of tonal characteristics, a departure may at times bedesirable from the effects produced by the sole action of any one ofthetranslating systems (e. g., strips 9, 10, 11 etc.) or by the jointaction of any two or more 'in any particular combination efl'ected as bythe switch-banks. Thus, for

example, a particular translating syst m, or

combination of such systems with particular put oscillations therefrombefore combinaamplitude and phase adjustments ofthe outa tone controlisfactory in the middle musical register, but at the same time mayprovide oscillations in the bass register which contain too highrelative amplitudes of lower partials. As a means of correcting this andsimilar difficulties, I show in the output circuit of tube 34 device 45,which may for example comprise an inductance 46, a capacity 47, and aresistance or potentiometer 48. W'ith the elements of the devicearranged as shown, either the inductance or the capacity may be madeeffective to shunt the output of tube 34, by adjustment of the variablecontact of the potentiometer toward that element. The potentiometer ispreferably of four times, or more than four times, the lowest value ofresistance which may be shunted across the output of this tube withnegligible effect on efficiency. This permits asetting of the movablecontact, i. e., at midposition electrically on the resistance of thepotentiometer, such that negligible effect, when desired, is felt fromthe inclusion of the device in circuit. The choice of inductance andcapacity values may readily be determined with the aid of principleswell understood in the art of audio-frequency amplification, regardbeing had for particular results desired in a given case.

It will be understood, of course, that the more effective be theinductance as a shunt across the line, the greater will be theattenuati0n of lower partials of the bass tones produced by the system.On the other hand, the more effective be the capacity as a shunt,

' the greater will be the attenuation of the higher frequencies,particularly of the higher partials of the high treble tones. It willfurther be understood that the tone control device shown illustrativeonly, any of several well-known circuits and/or devices directed tosimilar ends being capable of substitution therefor.

Such tone control devices may further be employed, and I hereinafterclaim as my invention their employment, to control one or more of theseparate series of oscillations before combination thereof by thecombining apparatus. Thus I have shown a similar tone control device 45in the output of each of the three tubes 21, 22 and 23. In this positionthey may be made to produce a wide variety of effects; including that ofan accentuation of either very low or very high frequencies, which isaccomplished by attenuating that range of frequencies in one of two setsof oscillations derived from two translating devices or systems andbeing principally opposed against each other, at least as to theircomponents in that range, by the phase ad uStment effected by theswitch-banks or equivalent combining system.

When each translating system, e. g., strip 9, 10-, 11, etc., ispositioned opposite a corresponding fractional-position of each string,

tends to be uniform in action with respect to the translation ofparticular partials of the vibration of each string. This condition maynot always be desirable; and as a method of providing departure fromsuch uniformity of particular partial translation characteristics in arational manner, I have included illustrative Figure 3. Here thefractional distance of each strip 9,10, 11, 12 and 13 from therespectively nearer end of the string will be seen to be progressivelyless, the longer the string; but the ratios between themselves of thespacings of the several strips from such ends of each string have thewhole system shown in Figure 2 being available to produce v thesediscriminating effects.

Occasionally it may be desired to produce for some musical purpose apractically pure tone; or, again, practically pure tones may be desiredat some point in a musical instrument in which a desired harmonicstructure is built up by synthetizing a group of harmonically relatedsuch tones. To obtain such a tone from a string or other mechanicalvibrator vibrating with a complement of partial frequencies, I show inFigure 4 a special arrangement of translating devices. Thus threeconductive strips 18, 19 and 20 may be provided, positioned at A,, andA-of -active string length respectively from the front end of the activeportion of the string. These three strips may be electrically connectedtogether and to the input of an electrical system similar to that shownin Figure 1- e. g., to thegrid to tube 21 in that figure. trips 18 and20 must be similarly spaced from string 1, thus producing oscillationshaving a similar amplitude of fundamental component; and the spacing ofstrip 19 from string 1 may be adjusted until the amplitude offundamental component produced by it is twice that produced by each ofthe other two devices. Under these conditions no 3rd, 5th, 11th, or13th, partials will be present in the output oscillations; whichcondition will be found convenient as a test for proper position ofstrip 19. Due to the symmetry of strips 18 and 20 about the longitudinalcenter of the string, and to their aiding connection, they jointlytranslate no even partials; strip 19 being at string, where no evenpartial vibrationv takes place, consequently translates none; and thethe same distance from the center of the.

3rd, 5th, 11th and 13th as abovementioned.

Consequently of the partia's up to and including the 14th, only the 7thand 9th are translated; and if string vibration 'at these partialfrequencies be kept low by the exciting means, as by hammer 8 strikingstring 1 partial are eliminated at approximately 1/8 its active lengthback of the front end thereof, as is well understood in the iano art,the net upper partial content 'of the translated" oscillations will bevery low. Furthermore for at least a limited range of simultaneouslyavailable musical notes, these upper partials may be reduced to anegligible value by means of the tone control device in the output oftube 21 and/or of tube 24. Tubes 22 and 23 and associated apparatus neednot, of course, be employed in this embodiment of my invention.

It will be understood that while I have shown and described anelectrostatic form of translating device or system, the principles of myinvention are equally applicable to any other form .of translatingdevice or system which may be associated with, and be actuated by thevibration of, particular portions of the vibrators. It will further beunderstood that while I have shown tapped resistors 41, 42 and 43, andbanks of switches 51, 52 and 53, for controlling the amplitudes andphases of the separate series of oscillations before combinations, otherforms of amplitude and phase controls such for example as tappedresistors and multipoint single-pole switches, or center-tappedPotentiometers, may be substituted therefor, or the variable controlsentirely omitted when selective artlcular partial translation is notrequired, and the other features of my invention at the same timeretained. It will finally be un-. derstood that the apparatus andcircuits shown are capable of wide modification with- 'out departure inthe combinations, or

methods of use, thereof from the spirit or scope of my invention, ashereinabove dis-.

closed and'in the appended claims defined.

I claim 1. In a musical instrument, the combination of a plurality oftuned vibrators; means for vibrating said vibrators; a plurality ofmechanico-electric translating systems, each system being associatedwith a portion of each vibrator different from that with which each said55 be other system is associated and ing arranged .to translate into aseries of electric oscillations the vibrations of the therewithassociated such portions; adjustable'meansindividually operative on atleast one of said series of oscillations for altering the relativeamplitudes of components thereof on an absolute frequency basis; andmeans following said adjustable means for combining the oscillations ofthe several such.

series.

2. In a 'muslcalmstrument, the combinetion-of a plurality of tunedvibrators;imeans for vibrating said vibrators; a plurality ofmechanico-electric translating systems, each system being associatedwith a portion of 'each vibrator different from that with which eachsaid other system is associated and being arranged to translate into aseries of electric oscillation. the vibrations of the therewithassociated such portions; selective means for varying thecharacteristics of the oscillations of the several such series relativeto each other; adjustable means individually operative on at least oneof said series of oscillations for'altering the relative amplitudes ofcomponents thereof on an absolute frequency basis; and means followingsaid selective and adjustable means for combining the oscillations ofthe several such series.

3. In a musical instrument, the combination of a plurality of tunedvibrators; means for vibrating each of said vibrators; a plurality ofsystems each for translating into a series of electric oscillations thevibration of a difierent portion of each of said vibrators; a pluralityof electric work circuits; means for applying the oscillations of eachof-such series across a respective such work circuit to develop avoltage therein; a plurality of taps-on each said work circuit; and anelectrical circuit, including a plurality of two-position switchesindividually connected to said taps, wherein voltages from said workcircuits may be variously combined.

4. In a musical instrument, the combination of a tuned string; means forvibrating said string; two mechanico electric translating devicespositioned on opposite sides of said string, respectively adjacentportions thereof having a slight longitudinal'separation, each fortranslating the vibration-of the adjacent said portion into a series ofel ectric oscillations; and means for combining said two series ofoscillations.

5. In a musical instrument, the combination of a tuned string; means forvibrating said string; two mechanico-electric trans lating devices.respectively adjacent two points on said string which divide the activelength thereof-into three parts of which the outside two aresubstantially equal, eachpf said sys tems being arranged to translateinto a series .of electric oscillations the vibration of the adjacentsaid point; and means for combinins! said two series of oscillations.

6. In a musical instrument, the combination of a tuned string; means forvibrating said string; two mechanico-electric translating devices,respectively adjacent two points on said string which divide the activelength thereof into three arts of which the outside two aresubstantially equal, eachof said systems being arranged to translateinto a setranslating device adjacent a point of said string distant byone-quarter of its active length from one end thereof and amechanicoelectric translating device similarly adjacent I a point ofsaidstring distant by three-quarters of its active length from said endthereof, each of said translating devices being arranged to translateinto a series of electric oscillations the vibration of the adjacentsaid point; a mechanico-electric translating device adjacent the centralpoint of the active length of said string and arranged to translate thevibration of said central point into a series of electric oscillationshaving a .fundamental frequency component substantially double that of,each of said two first mentioned series; and means for combining saidthree series of oscillations additively with respect to'theirfundamental frequency components.

8. The combination of a string; means for vibrating said string; amechanico-electric translating device adjacent a point on said stringdistant by one-quarter of its active length from one end thereof and amechanicoelectric translating device similarly adjacent a point of saidstring distant by three-quarters of its active length from said endthereof, each of said translating devices being arranged to translateinto a series of electric oscillations the vibration of the adjacentsaid point; a mechanico-electric translating device positioned oppositethe central point of theactive length of said string and arranged totranslate the vibration of said central point into a series of electricoscillations having a fundamental frequency component substantiallydouble that of each of said two first-mentioned series; means forcombining said three series of oscillations additively with respect totheir fundamental frequency components; and means for attenuatingresidual upper partial components from said combined oscillations.

9. In a musical instrument, the combination of a plurality of stringstuned to progressive fundamental frequencies; means for vibrating saidstrings; a mechanico-electric translating system associated with, andarranged to translate into a series of electric oscillations thevibration .of, a point on each string, the distances of said points fromthe ends of the respective strings having a progressive relation to therespective-lengths of said strings; at least one other mechanicoelectrictranslating system, each said other system being adjacent, and arrangedto translate into a series of electric oscillationsthe vibration of,another point on each string, the distances of saidlast named pointsfrom the ends of the respective strings being a substantially constantmultiple of the respective said first-mentioned distances; and means forcombining said series of oscillations.

10; In a musical instrument, the combination of a plurality of tuned,electrically conductive vibrators; a plurality of electricallyconductivemembers, each said member being positioned adjacent a portion of each ofsaid vibrators different from that to which each other said member isadjacent and forming electrical capacities with said portions; anelectrical work circuit unilaterally connected to said vibrators; asource of D. (1.

means for connecting said conductive members selectively to said workcircuit.--

11. In a musical instrument, the combination of a plurality of tuned"vibrators; means for vibrating said vibrators;'a plurality ofelectrical work circuits; a, number greater translating systems, eachsystem being associated with a portion of each of said vibratorsdifferent from that with which each said other system is associated andbeing arranged to translate-into a series of electric oscillations thevibrations of the therewith associated said portions; and meansinterposed between said translating devices and said work circuits, andselective with respect both to said translating systems andto said workcircuits, for applying to said work circuits said various series ofoscillations.

12. The method of producing electric oscillations from a tuned vibratorand of regulating their harmonic structure, which consists in vibratingsaid vibrator at a plurality of its partial frequencies, in translatingthe vibrations of each of a plurality of por- "tions of saidvibrator'into a series of electric oscillations, in attenuatingcomponents of the oscillations of one of said series in a degree varyingwith absolute frequency, and in thereafter combining theoscillations ofthe several such series.

13. The method of producing electric oscillations from a tuned vibratorand of regulating their harmonic structure, which consists in vibratingsaid vibrator at a plurality of its I partial frequencies, intranslating the vibrations of each of a plurality of different portionsof said vibrator into a series of elec-.

tric oscillations, in regulatin the characteristics of the oscillationsof t e several such series relative to each other, in attenuatingcomponents of the oscillations of one of said series in a degree varyingwith absolute frequency, and in thereafter-combiningthe oscillations ofthe several. such series.

14. The method of producing electric oscillations in which alternatelynumbered par- ,potentialincluded in said work circuit; and p than saidplurality of mechanico-electrictials predominate from a tuned string,which consists in vibratlng said string at a plurality of its partialfrequencies, in translating intoa series of electric oscillations thevibration of each of two portions of said string substantiallysymmetrically located longitudinally about the center of the activelength of said string, and in combining the oscillations of the two suchseries.

15. The method of producing electric oscillations from a tuned stringand of varying their harmonic structure, which consists in vibratingsaid string at a plurality of its partial frequencies, in translatinginto a series of electric oscillations the vibration of each of twoportions of-said string substantially symmetrically locatedlongitudinally about the center of the active length of said string, inregulating the characteristics of the two such series relative to eachother, and

in thereafter combining the oscillations of the two such series.

16. The method of generating electric oscillations of substantially purefundamental frequency from a timed string, vibrating at its fundamentaland other of its partial frequencies, which consists in translating intoa series of electric oscillations the vibration of a point on saidstring distant by one quarter of the active length of said string fromone .end thereof, in translatinginto a series of electric oscillationsof similar funda: mental component amplitude the vibration of a point onsaid string distant by three quarters of the active length of saidstring from said end thereof, in translating into a series of electricoscillations having a fundamental component twice that of each of saidtwo first;mentioned series the vibration of the central point of theactive length of said string, and in combining said series ofoscillations additively with respect to their fundamental components.

17. The method of generating electric oscillations ofsubstantially purefundamental frequency from a tuned string vibrating at its fundamentaland other of its partial frequencies, which consists in translating intoa series of electric oscillations the vibration of a point on saidstring distant by one quarcomponents, and in attenuating residual up perpartial components of said combined oscillations.

CHARLES T. JACOBS.

